The legendary German conductor Otto Klemperer was one of the most profound musicians of the 20th Century. In the 1960s, nearing the end of his career, he overcame many physical handicaps to create an astonishing body of recorded classical music. EMI has just reissued a broad spectrum of his recordings, including a box set of one of the composers he's most associated with: Gustav Mahler. Fresh Air classical music critic Lloyd Schwartz has a review of Mahler: Symphonies 2, 4, 7 & 9 / Das Lied von der Erde.